Method and system for fabricating a composite structure

Abstract

A method and system for fabricating a composite structure is provided. At least a first layer of reinforcement material is placed on a surface of a tool. At least a first layer of veil material is then wrapped around the first layer of reinforcement material while the first layer of reinforcement material is positioned on the tool to produce a first reinforced ply.

The invention claimed is: 
     
       1. A method of fabricating a composite structure, the method comprising:
 placing at least a first layer of reinforcement material on a surface of a tool; and 
 wrapping at least a first layer of veil material around the first layer of reinforcement material while the first layer of reinforcement material is positioned on the tool to produce a first reinforced ply, wherein the step of wrapping the first layer of veil material comprises relative axial rotation and longitudinal movement between the tool and a spool of veil material to spirally wrap the first layer of veil material around the first layer of reinforcement material such that adjacent pitches of the first layer of veil material overlap one another, and wherein a speed of the relative axial rotation and longitudinal movement between the tool and the spool of veil material is varied during the wrapping so as to provide a variable overlap of adjacent pitches of the first layer of veil material such that an amount of the first layer of veil material applied to the first layer of reinforcement material is varied along a length of the first reinforced ply such that a strength of the first reinforced ply is varied along its length. 
 
     
     
       2. The method of  claim 1 , further comprising placing at least a second layer of reinforcement material on the first layer of veil material while the first reinforced ply is positioned on the surface of the tool. 
     
     
       3. The method of  claim 2 , further comprising wrapping at least a second layer of veil material around the second layer of reinforcement material while the second layer of reinforcement material is positioned on the tool, the second layer of reinforcement material and the second layer of veil material forming a second reinforced ply on the first reinforced ply. 
     
     
       4. The method of  claim 1 , wherein the step of placing the first layer of reinforcement material on the surface of the tool comprises placing the first layer of reinforcement material on a surface of a mandrel. 
     
     
       5. The method of  claim 1 , wherein the step of wrapping the first layer of veil material comprises rotating the tool about an axis, whilst keeping the tool longitudinally stationary, and longitudinally advancing the first layer of veil material. 
     
     
       6. The method of  claim 1 , wherein the step of wrapping the first layer of veil material comprises keeping the tool axially and longitudinally stationary whilst rotating the veil material axially around the tool and longitudinally advancing the first layer of veil material. 
     
     
       7. The method of  claim 1 , further comprising:
 adding a resin to at least the first reinforced ply to form a composite layup; and 
 curing the resin in the composite layup to form the composite structure. 
 
     
     
       8. The method of  claim 1 , further comprising intermediately heating at least the first reinforced ply to form at least a first stabilized preform. 
     
     
       9. A system for fabricating a composite structure, the system comprising:
 a tool having a surface for supporting at least a first layer of reinforcement material placed on the tool surface; 
 a wrapping device configured to wrap at least a first layer of veil material around the first layer of reinforcement material while the first layer of reinforcement material is positioned on the tool to produce a first reinforced ply; and 
 a drive device configured to cause relative axial rotation and longitudinal movement between the tool and the wrapping device such that the first layer of veil material is spirally wrapped around the first layer of reinforcement material while the first layer of reinforcement material is positioned on the tool such that adjacent pitches of the first layer of veil material overlap one another, wherein the drive device is configured to provide a variable speed of the relative axial rotation and longitudinal movement between the tool and the wrapping device so as to provide a variable overlap of adjacent pitches of the first layer of veil material such that an amount of the first layer of veil material around the first layer of reinforcement material is varied along a length of the first reinforced ply such that a strength of the first reinforced ply is varied along its length. 
 
     
     
       10. The system of  claim 9 , wherein the tool is configured to support at least a second layer of reinforcement material on the first layer of reinforced material. 
     
     
       11. The system of  claim 10 , wherein the wrapping device is configured to wrap at least a second layer of veil material around the second layer of reinforcement material to produce a second reinforced ply on the first reinforced ply. 
     
     
       12. The system of  claim 9 , further comprising a veil material tensioner adapted to apply tension to at least one of the first layer of veil material and a second layer of veil material relative to the tool. 
     
     
       13. The system of  claim 9 , further comprising:
 a resin supplier configured to add a resin to the first reinforced ply to form a composite layup; 
 a heat source configured to heat the composite layup to cure the resin and form the composite structure; and 
 a vacuum bag configured to contain the composite layup during curing. 
 
     
     
       14. The method of  claim 1 , further comprising:
 applying tension to the first layer of veil material prior to wrapping the first layer of veil material around the first layer of reinforcement material. 
 
     
     
       15. The system of  claim 12 , wherein the veil material tensioner is configured to vary a magnitude of the tension applied to at least one of the first layer of veil material and a second layer of veil material relative to the tool at different time periods during the wrapping process. 
     
     
       16. The system of  claim 12 , wherein the tension applied to at least one of the first layer of veil material and a second layer of veil material relative to the tool is constant throughout the wrapping process. 
     
     
       17. The method of  claim 14 , wherein a magnitude of the tension applied to the first layer of veil material is configured to vary at different time periods during the wrapping process. 
     
     
       18. The method of  claim 2 , further comprising:
 applying tension to the second layer of veil material prior to wrapping the second layer of veil material around the second layer of reinforcement material. 
 
     
     
       19. The method of  claim 18 , wherein a magnitude of the tension applied to the second layer of veil material is configured to vary at different time periods during the wrapping process. 
     
     
       20. The system of  claim 12 , wherein the veil material tensioner comprises a brake configured to control a spool in the wrapping device.